A research report by Brent H. Tisserat, Edward B. Esan and Toshio Murashige entitled "Asexual Enbryogenesis in Angiosperms" is the most recent and exhaustive report on asexual embryogenesis in vitro known to applicants.
A section of that report states that:
"Table 2 lists the plants, the tissue cultures of which have been reported to generate asexual embryos."
Their Table 2 purports to be a complete survey and does include a few cotyledoneous explants, but there is at least one significant omission, namely cacao, and a further section of the report, entitled "Morphological Aspects of Asexual Embryogeny in Vitro" makes it apparent that the authors have described the current state of the art solely in terms of its agricultural impact, namely the aspect of plant reproducibility, and not in any sense have they related embryogenesis to the use to which it is put by applicants.
The authors thus state their conclusion to be:
"Asexual embryogenesis might be viewed as reflecting a failure of normal development. Nevertheless, it has practical agricultural significance. It enables clonal propagation of some species. The plants derived through asexual embryogeny are often free of many pathogens, especially viruses, that might have infected the original plant (Bitters et al., 1970). Its manifestation in tissue cultures might be used advantageously in clonal multiplication of cultivars that are currently propagated by seeds. We foresee in the very near future clonal seeds from asexual embryos produced in vitro.
The naturally highly polyembryogenic situation has been an obstacle in plant breeding, since it is usually difficult, if not impossible, to distinguish and separate the zygote embryo from the asexual embryos. Methods are needed to enable separation of the two kinds of embryo or to selectively suppress development of the asexual ones."